Potable water quality monitoring of primary schools in Magura district, Bangladesh: children's health risk assessment.

Safe potable water is essential for good health. Worldwide, school-aged children especially in the developing countries are suffering from various water-borne diseases. In the study, drinking water supplies for primary school children were monitored at Magura district, Bangladesh, to ensure safe potable water. APHA standard analytical methods were applied for determining the physicochemical parameters of the water samples. For determination of the essential physicochemical parameters, the samples were collected from 20 randomly selected tube wells of primary schools at Magura. The metal contents, especially arsenic (As), iron (Fe), and manganese (Mn), in the water samples were analyzed by atomic absorption spectroscopy. The range of physicochemical parameters found in water samples were as follows: pH 7.05-9.03, electrical conductivity 400-2340 µS/cm, chloride 10-640 mg/L, hardness 200-535 mg/L as CaCO3, and total dissolved solids 208-1216 mg/L. The level of metals in the tube well water samples were as follows: As 1 to 55 µg/L, Fe 40 to 9890 µg/L, and Mn 10 to 370 µg/L. Drinking water parameters of Magura district did not meet the requirement of the World Health Organization drinking water quality guideline, or the Drinking Water Quality Standards of Bangladesh.

High sensitivity arsenic analyzer based on liquid-reagent-free hydride generation and chemiluminescence detection for on-site water analysis.

In this work, a portable and reliable instrument based on manual hydride generation and subsequent ozone induced chemiluminescence analysis was developed and optimized for measurement of aqueous arsenic in drinking water. The aim was to develop a system for use in the field in villages in developing countries where water treatment systems have been installed. Consequently, it is beneficial that the system could be operated without reagent solutions or purified water. Arsenic trihydride (arsine) was generated by reaction with solid acid and solid borohydride, and then introduced to a chemiluminescence cell where the arsine was mixed with ozone to generate chemiluminescence. The measurement could be repeated with the throughput of 60 times h(-1), and the limit of detection was 0.4 µg L(-1). The measurable arsenic concentration was up to 1 mg L(-1) for 2 mL samples. The system was evaluated for analysis of natural water samples, and the obtained data agreed well with those from ICP-MS and sequential hydride generation flow analysis. We expect this small and inexpensive instrument will be used in developing countries.

Effect of potassium simplex optimization medium and NCSU23 supplemented with beta-mercaptoethanol and amino acids of in vitro fertilized porcine embryos.

The present study was conducted to examine the comparative efficacy of potassium simplex optimization medium (KSOM) and North Carolina State University (NCSU)-23 medium supplemented with beta-mercaptoethanol (beta-ME) and amino acids (AA) on the developmental competence of porcine in vitro fertilized (IVF) embryos. Four experiments were conducted. KSOM and NCSU-23 medium were used to culture porcine parthenogenetic (Exp. 1) and IVF (Exp. 2) embryos. KSOM and NCSU-23 were equally effective in supporting porcine parthenogenetic and IVF embryo development from the 1-cell stage to blastocysts. The NCSU-23 medium (Exp. 3) and KSOM (Exp. 4) were supplemented with amino acid (AA; 5 microl/ml non-essential amino acids + 10 microl/ml essential amino acids) and/or 10 microM beta-mercaptoethanol (beta-ME). The quality of blastocysts from Exp. 3 and 4 was evaluated by counting the number of total cells and determining the ratio of the inner cell mass (ICM) to trophoectoderm (TE) cells. Supplementing with AA and beta-ME or beta-ME alone in NCSU-23 produced significant (p<0.05) differences in terms of rate of cleavage to the 2- to 4- cell (80.8 to 85.4% vs. 73.6%) and blastocyst (30.4 to 30.5 vs. 23.5%) stages and the number of TE (51.4 to 53.8 vs. 35.8) and total cells (67.2 to 71.2 to 48.8) over the control group. On the other hand, supplementing KSOM with AA and/or beta-ME produced significant (p<0.05) differences in terms of rate of cleavage to the 2- to 4-cell (78.8% vs. 67.7%) and morula (57.8% vs. 46.3%) stages and the number of ICM (18.6 to 19.2 vs. 11.6) and total cells (62.8 to 70.6 vs. 42.8) over control group. In conclusion, our study demonstrates that both KSOM and NCSU-23 medium supplemented with AA and beta-ME and/or only beta-ME alone are superior to normal KSOM and NCSU-23 for porcine IVF embryo culture in terms of embryo developmental competence and quality.

Cross-resistance to imidazolinone herbicides in chlorsulfuron-resistant Raphanus raphanistrum.

Raphanus raphanistrum L has evolved widespread resistance to sulfonylureas in the Western Australia (WA) wheat belt. With the introduction of imidazolinone-tolerant (IT) wheat (Tritcum aestivum L) and IT canola (Brassica napus L) in the WA wheat belt, it is important to understand the status of cross-resistance in this weed to sulfonylurea and imidazolinone (Imi) herbicides. A study was conducted to examine cross-resistance between chlorsulfuron and Imi herbicides (a mixture of imazapic and imazapyr) in 46 R raphanistrum populations collected from across the WA wheat belt. Plants were treated with herbicides and assessed for phytotoxicity under glasshouse conditions. Of the 46 R raphanistrum populations, 32 were resistant to chlorsulfuron and four were resistant to imazapic + imazapyr. Of the 70% chlorsulfuron-resistant populations, 13% showed cross-resistance to imazapic + imazapyr. However, the cross-resistant populations treated with imazapic + imazapyr showed a lower resistance level than the chlorsulfuron-treated populations. These results suggest that weed populations with such cross-resistance will not be controlled effectively by Imi herbicides. Although the resistance levels of the cross-resistant populations to Imi herbicides were low, the cross-resistance levels of R raphanistrum should be determined before growing IT crops, particularly IT canola.